The present invention relates generally to radiation detectors, and particularly to radiation detectors using radiation sensing elements whose range of detectable wavelengths has been enhanced via the presence of luminescent materials.
Description of Related Art
Conventional radiation detectors utilizing photodiodes are generally limited in the range of wavelengths that they can detect; for example conventional silicon photodiodes are not efficient in detecting ultraviolet (UV) rays, and germanium photodiodes are generally used in the infrared (IR) range. It would be highly desirable to be able to extend the range of photodiodes and other radiation sensing elements (such as charge-coupled device arrays (CCD), photomultiplier tubes (PMT) and IR detectors) to be able to detect wavelengths with greater efficiencies than their present capability.
U.S. Pat. No. 5,115,138 discloses a UV detecting device comprising an external light shielding means, a fluorescent member disposed in said external light shielding means, a light entrance means, a means to extract UV rays and guide said rays to said fluorescent member, and a photodiode. The fluorescent member upon absorption of the UV rays fluoresces, said fluorescent radiation being detected by the photodiode. It would be highly desirable to be able to eliminate the need for external shielding means and the means for extracting UV rays from the incident light. In addition the device according to U.S. Pat. No. 5,115,138 does not permit the determination of the wavelength of the radiation detected.
U.S. Pat. No. 5,196,705 discloses a luminescing dye contained in a sensing sheet which luminesces in response to incident UV light in a selected range, said luminescent light being detected by a sensor. However these materials are limiting because of the difficulty of forming luminescent dye materials into thin films, and by its self quenching properties.